#include<bits/stdc++.h>
using namespace std;
#define N 330
typedef long long LL;
LL a[N];

int main(){
    int n;
    cin>>n;
    LL b = 0;
    for(int i = 1; i <= n; i++){
        scanf("%lld", &a[i]);
        b ^= a[i];
    }
    
    
}